php上传文件常见问题(基础)

既然上一篇文章《php上传中文文件文件名乱码问题》遇到了文件上传的问题，干脆把php上传文件时经常碰到的几个问题总结一下吧，以后用到时不用再去找了。

1.先做个最简单的上传文件

<span> 1</span> <span><span>html</span><span>></span>
<span> 2</span> <span><span>head</span><span>></span>
<span> 3</span> <span><span>meta </span><span>http-equiv</span><span>="Content-Type"</span><span> content</span><span>="text/html; charset=utf-8"</span><span>></span>
<span> 4</span> <span></span><span>head</span><span>></span>
<span> 5</span> <span><span>body</span><span>></span>
<span> 6</span> 
<span> 7</span> <span><span>form </span><span>action</span><span>="upload_file.php"</span><span> method</span><span>="post"</span>
<span> 8</span> <span>enctype</span><span>="multipart/form-data"</span><span>></span>
<span> 9</span> <span><span>label </span><span>for</span><span>="file"</span><span>></span>Filename:<span></span><span>label</span><span>></span>
<span>10</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="file"</span><span> id</span><span>="file"</span> <span>/></span> 
<span>11</span> <span><span>br </span><span>/></span>
<span>12</span> <span><span>input </span><span>type</span><span>="submit"</span><span> name</span><span>="submit"</span><span> value</span><span>="Submit"</span> <span>/></span>
<span>13</span> <span></span><span>form</span><span>></span>
<span>14</span> 
<span>15</span> <span></span><span>body</span><span>></span>
<span>16</span> <span></span><span>html</span><span>></span></span></span></span></span></span></span></span></span></span>

<span> 1</span> <span>php
</span><span> 2</span> <span>if</span> ((<span>$_FILES</span>["file"]["size"] )
<span> 3</span> <span>  {
</span><span> 4</span>   <span>if</span> (<span>$_FILES</span>["file"]["error"] > 0<span>)
</span><span> 5</span> <span>    {
</span><span> 6</span>     <span>echo</span> "Return Code: " . <span>$_FILES</span>["file"]["error"] . "<br>"<span>;
</span><span> 7</span> <span>    } 
</span><span> 8</span>   <span>else</span>
<span> 9</span> <span>    {
</span><span>10</span>     <span>echo</span> "Upload: " . <span>$_FILES</span>["file"]["name"] . "<br>"<span>;
</span><span>11</span>     <span>echo</span> "Type: " . <span>$_FILES</span>["file"]["type"] . "<br>"<span>;
</span><span>12</span>     <span>echo</span> "Size: " . (<span>$_FILES</span>["file"]["size"] / 1024) . " Kb<br>"<span>;
</span><span>13</span>     <span>echo</span> "Temp file: " . <span>$_FILES</span>["file"]["tmp_name"] . "<br>"<span>;
</span><span>14</span> 
<span>15</span>     <span>if</span> (<span>file_exists</span>("upload/" . <span>$_FILES</span>["file"]["name"<span>]))
</span><span>16</span> <span>      {
</span><span>17</span>       <span>echo</span> <span>$_FILES</span>["file"]["name"] . " already exists. "<span>;
</span><span>18</span> <span>      }
</span><span>19</span>     <span>else</span>
<span>20</span> <span>      {
</span><span>21</span>       <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"],
<span>22</span>       "upload/" . <span>$_FILES</span>["file"]["name"<span>]);
</span><span>23</span>       <span>echo</span> "Stored in: " . "upload/" . <span>$_FILES</span>["file"]["name"<span>];
</span><span>24</span> <span>      }
</span><span>25</span> <span>    }
</span><span>26</span> <span>  }
</span><span>27</span> <span>else</span>
<span>28</span> <span>  {
</span><span>29</span>   <span>echo</span> "Invalid file"<span>;
</span><span>30</span> <span>  }
</span><span>31</span> ?>

2.然后了解超级全局变量$_FILES的值 

$_FILES['userfile']['name']

$_FILES['userfile']['type']

$_FILES['userfile']['size']

$_FILES['userfile']['tmp_name']

$_FILES['userfile']['error']

其中,$_FILES['userfile']['error']的所有值：

UPLOAD_ERR_OK 其值为 0，没有错误发生，文件上传成功。

UPLOAD_ERR_INI_SIZE 其值为 1，上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值。

UPLOAD_ERR_FORM_SIZE 其值为 2，上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值。

UPLOAD_ERR_PARTIAL 其值为 3，文件只有部分被上传。

UPLOAD_ERR_NO_FILE 其值为 4，没有文件被上传。

UPLOAD_ERR_NO_TMP_DIR 其值为 6，找不到临时文件夹。PHP 4.3.10 和 PHP 5.0.3 引进。

UPLOAD_ERR_CANT_WRITE 其值为 7，文件写入失败。PHP 5.1.0 引进。

3.很多情况：需要严格判断上传文件类型

     我们知道使用$_FILES['userfile']['type']判断上传文件类型是一个很不明智的做法，因为该判断依据是文件的后缀名，任何人都可以将一个mp3文件的后缀改成jpg从而伪装成图片进行上传，因此php官方建议使用php的扩展php_fileinfo来判断文件的mime,开启拓展的方法百度一下有很多,win和linux略有不同。

4.情景一：上传文件重名后自动重命名

<span> 1</span> <span>if</span> (<span>file_exists</span>("./upload/" . <span>$_FILES</span>["file"]["name"<span>]))  
</span><span> 2</span> <span>{    
</span><span> 3</span>    <span>do</span><span>{  
</span><span> 4</span>        <span>$suffix</span> =""<span>;  
</span><span> 5</span>        <span>$suffix_length</span> = 4<span>;  
</span><span> 6</span>        <span>$str</span> = "0123456789abcdefghijklmnopqrstuvwxyz"<span>;  
</span><span> 7</span>        <span>$len</span> = <span>strlen</span>(<span>$str</span>)-1<span>; 
</span><span> 8</span>        <span>//</span><span>文件名后追加4个随机字符  </span>
<span> 9</span>        <span>for</span>(<span>$i</span>=0 ; <span>$i</span>$suffix_length; <span>$i</span>++<span>){  
</span><span>10</span>           <span>$suffix</span> .= <span>$str</span>[<span>rand</span>(0,<span>$len</span><span>)];  
</span><span>11</span> <span>       }  
</span><span>12</span>        <span>$upload_filename</span> = <span>$_FILES</span>['file']['name'<span>];                                            
</span><span>13</span>        <span>$filename</span> = <span>substr</span>(<span>$upload_filename</span>,0,<span>strrpos</span>(<span>$upload_filename</span>,".")).<span>$suffix</span>.".".<span>substr</span>(<span>$upload_filename</span>,<span>strrpos</span>(<span>$_FILES</span>["file"]["name"],".")+1<span>); 
</span><span>14</span>    }<span>while</span>(<span>file_exists</span>("./upload/".<span>$filename</span><span>));  
</span><span>15</span>        <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"],"./upload/" . <span>$filename</span><span>);  
</span><span>16</span> }<span>else</span><span>{  
</span><span>17</span>        <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"], "upload/" . <span>$_FILES</span>["file"]["name"<span>]);   
</span><span>18</span> }  

5.情景二：根据日期分目录上传文件 

<span>1</span> <span>$structure</span> = './'.<span>date</span>("Y").'/'.<span>date</span>("m").'/'.<span>date</span>("d").'/'<span>;
</span><span>2</span> 
<span>3</span> 
<span>4</span> <span>if</span> (!<span>mkdir</span>(<span>$structure</span>, 0777, <span>true</span><span>)) {
</span><span>5</span>     <span>die</span>('Failed to create folders...'<span>);
</span><span>6</span> <span>}
</span><span>7</span> 
<span>8</span> <span>move_uploaded_file</span>(<span>$_FILES</span>["file"]["tmp_name"],<span>$structure</span> . <span>$_FILES</span>["file"]["name"]);

6.情景三：多文件上传

<span>1</span> <span><span>form </span><span>action</span><span>=""</span><span> method</span><span>="post"</span><span> enctype</span><span>="multipart/form-data"</span><span>></span>
<span>2</span> <span><span>p</span><span>></span><span>Pictures:
</span><span>3</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="pictures[]"</span> <span>/></span>
<span>4</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="pictures[]"</span> <span>/></span>
<span>5</span> <span><span>input </span><span>type</span><span>="file"</span><span> name</span><span>="pictures[]"</span> <span>/></span>
<span>6</span> <span><span>input </span><span>type</span><span>="submit"</span><span> value</span><span>="Send"</span> <span>/></span>
<span>7</span> <span></span><span>p</span><span>></span>
<span>8</span> <span></span><span>form</span><span>></span></span></span></span></span></span></span>

<span>1</span> <span>php
</span><span>2</span> <span>foreach</span> (<span>$_FILES</span>["pictures"]["error"] <span>as</span> <span>$key</span> => <span>$error</span><span>) {
</span><span>3</span>     <span>if</span> (<span>$error</span> ==<span> UPLOAD_ERR_OK) {
</span><span>4</span>         <span>$tmp_name</span> = <span>$_FILES</span>["pictures"]["tmp_name"][<span>$key</span><span>];
</span><span>5</span>         <span>$name</span> = <span>$_FILES</span>["pictures"]["name"][<span>$key</span><span>];
</span><span>6</span>         <span>move_uploaded_file</span>(<span>$tmp_name</span>, "data/<span>$name</span>"<span>);
</span><span>7</span> <span>    }
</span><span>8</span> <span>}
</span><span>9</span> ?>

有的情况下多文件的这种变量结构并不好用：

array(1) {

    ["upload"]=>array(2) {

        ["name"]=>array(2) {

            [0]=>string(9)"file0.txt"

            [1]=>string(9)"file1.txt"

        }

        ["type"]=>array(2) {

            [0]=>string(10)"text/plain"

            [1]=>string(10)"text/html"

        }

    }

}

很多情况下我们需要的是类似这样的结构

 

array(1) {

    ["upload"]=>array(2) {

        [0]=>array(2) {

            ["name"]=>string(9)"file0.txt"

            ["type"]=>string(10)"text/plain"

        },

        [1]=>array(2) {

            ["name"]=>string(9)"file1.txt"

            ["type"]=>string(10)"text/html"

        }

}

}

使用下面的函数就能轻松转化结构

<span>1</span> <span>function</span> diverse_array(<span>$vector</span><span>) { 
</span><span>2</span>     <span>$result</span> = <span>array</span><span>(); 
</span><span>3</span>     <span>foreach</span>(<span>$vector</span> <span>as</span> <span>$key1</span> => <span>$value1</span><span>) 
</span><span>4</span>         <span>foreach</span>(<span>$value1</span> <span>as</span> <span>$key2</span> => <span>$value2</span><span>) 
</span><span>5</span>             <span>$result</span>[<span>$key2</span>][<span>$key1</span>] = <span>$value2</span><span>; 
</span><span>6</span>     <span>return</span> <span>$result</span><span>; 
</span><span>7</span> <span>} 
</span><span>8</span> <span>$upload</span> = diverse_array(<span>$_FILES</span>["upload"]);

7. 有的时候：需要配置服务器修改最大上传文件大小

首先，在表单上

<span><span>input </span><span>type</span><span>="hidden"</span><span> name</span><span>="MAX_FILE_SIZE"</span><span> value</span><span>="字节"</span> <span>/></span></span>

可以限制上传文件大小（可以被绕过）。

然后在服务器上也需要调整一下配置

php.ini:

max_execution_time = 30 每个脚本运行的最长时间，单位秒
max_input_time = 60，每个脚本可以消耗的时间，单位也是秒
memory_limit = 128M，这个是脚本运行最大消耗的内存
post_max_size = 8M，表单提交最大数据为 8M，此项不是限制上传单个文件的大小,而是针对整个表单的提交数据进行限制的。
upload_max_filesize = 2M ，上载文件的最大许可大小 

nginx:

<span>1</span> <span>location / {
</span><span>2</span>     root   html<span>;
</span><span>3</span>     index  index.html index.htm<span>;
</span><span>4     </span>client_max_body_size    1000m<span>;
</span><span>5</span>  }

以上就介绍了php上传文件常见问题(基础)，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。